chemistry journal of moldova

Chemistry Journal of Moldova. G. Vasile General, et al./Chem.J. Industrial Mold. and 2008, Ecological 3 (1), 56-61 Chemistry. 2008, 3 (1), 56-61STUDY ON QUANTITATIVE SPECIATION, BY BCR METHOD, OF ZINCCONTENT FROM RIVER SEDIMENTSGeorgiana Vasile*, Stanescu Bogdan, Tudor Claudia, Elena MihailaNational Research and Development Institute for Industrial Ecology – ECOIND 90-92 Panduri Road, 050663,Bucharest, sector 5, Romania*Corresponding author: phone: +40/21/4100377; fax: +40/21/4100575; e-mail: ecoind@incdecoind.roKeywords: sediment, sequential extraction, bioavailability, zinc mobility.An unwanted consequence of human activity and of uncontrolled industrialization is the environment contaminationwith a lot of pollutants, among them heavy metal anthropogenic pollution having some most serious consequences. Areliable estimation of pollution level is made by studying heavy metal concentrations in the sediments.In our study the zinc content of the water and river sediments has been investigated, in an area polluted bymining activities, to provide information on the mobility and availability of this element. Sediment and water sampleshave been collected from significant sites in a former mining area in which with some sterile pits, which represent amajor environmental hazard.The zinc mobility and bioavailability in the environment was investigated by the three-step sequential extractionprocedure, a protocol proposed by the Standards, Measurements and Testing programme (SM & T–formerly BCR)of the European Union. The BCR sequential extraction scheme has the advantage that there are reference materialsavailable with certified and indicative values for the concentrations of selected elements in the particular extractionsteps. The BCR procedure enables fractionalization of metal content into the following fractions:EASILY MOBILIZABLE FRACTION: This fraction contains the specifically bound, surface occluded species(sometimes also CaCO3 bound species and metallo-organic complexes with low bonding forces).ORGANICALLY BOUND FRACTIONMn-Fe-and Al-OXIDE BOUND FRACTIONRESIDUAL FRACTION: This fraction mainly contains crystalline-bound trace metals and is most commonlydissolved with high concentrated acids and special digestion procedures.Combination of data from sequential extraction procedures and normalisation approaches provides a good basisto estimate the proportions of the easily and sparingly soluble metal fractions in the samples investigated and to identifythe anthropogenic input of metals into the environment.IntroductionFrom the pollution types that are to be found in our country, the most prevalent and having powerful effects forthe quality of surface waters and of the sediments, is the heavy metals pollution that is to be found especially in the areashaving a long ores extraction activity.Understanding the importance of sediments role in contaminants transport and storage, conduced to an increasingpreoccupation of the researchers and of the organisms responsible for the control and the prevention of water pollution,in the pollutant compounds knowledge field.For an evaluation of heavy metals charge in the sediments, is not sufficient to determinate their total concentration.The establishment of the metals proportions in easy soluble fractions and in the hard soluble ones is very important.These fractions evaluation allows the elucidation of their existing dangers and seriousness for the aquaticecosystems [1].The signification of speciation analyze as a method for estimating the environment risk was recognized by theEnvironment Conservation Council from Australia and New Zeeland (ANEZECC), who recommanded the examinationof bioaccesible concentrations, where the metals total levels overpass the levels established into the Interimare QualityCriteria for Sediments[2].For the estimation of the natural and the anthropogenic inputs of the heavy metals in the sediments, are usedidentification methods by sequential chemical extraction (BCR technique) and normalizations, based on the correlationsbetween the concentrations of the elements present in the tracks, and an element that is naturally present in theinvestigated environment [3].Further on are presented the results of the researches effectuated on sediments sampled from Certej River,which is affected by the long ore extraction activities. The papers that present the results in the thematic approach weredirected towards zinc content knowledge and towards the quantification of its existing forms in sediments.56